


Lullaby

by RAAMIsABeast



Series: Undertale One Shots [1]
Category: Undertale (Video Game)
Genre: Alternate Undertale Universes, Betting, Cute, Father-Son Relationship, Gen, Prompt Fic, Skeleton Child
Language: English
Status: Completed
Published: 2017-06-16
Updated: 2017-06-16
Packaged: 2018-11-14 23:17:14
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 894
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11218290
Author URL: https://archiveofourown.org/users/RAAMIsABeast/pseuds/RAAMIsABeast
Summary: Prompt: No one else is home and Gaster is forced to sing a lullaby to put Magneto to sleep.





	Lullaby

**Author's Note:**

> Gaster belongs to Toby Fox.
> 
> Psycho Vinnie belongs to a friend.
> 
> Leo, Aster and Magneto belong to me.

"See ya, Kid, G, K. Play nice, ya lil devil."

After Mafia Sans had warned his sometimes wayward pet to play nice, the others filtered through the funnel of a door, those who gave one wishing the lone shadow luck with the bouncing child currently occupied with the strange reptile christened Karma. To his credit, Karma loved the little ball of energy almost as much as he loved sleeping under the magically warm ribs of a certain Sans. Fetching the small metal ball after each admittedly pathetic (he was used to having to swim after it, give the water-lover some slack) fling, the creature would carry the ball back to the smiling, cheering, laughing, _annoying_ , tiny skeleton.

Moderate cracks stretched from each eye upwards and then down the tiny head, racing along the unblemished but not exactly smooth cranium and mandible to tease each other with connection at the base of the skull. Black magic swirled within a half-crescent moon plastered with a carefree smile. Every so often, a lilac tongue would spring forward like a jack-in-the-box, the child copying what he had witnessed an immature Sans (blasted Mafia and his devil-may-care attitude) do. Each blink hid away mini lilac eyes, a mixture of the shadow's darker purple and the true mother's lighter cyan ones.

"Dad, what's a 'stag do'?"

Childishly high and unusually sparky, the infinitesimal skeleton's voice was hard to not aw at and make cute gestures. Unless you were immune, like Gaster. Said Gaster glanced sideways, schooling his bones to show interest when all he wanted was to get his paperwork done. This free night - no one else but the one year old in his vicinity - was the older skeleton's to take and mold into whatever he wished with it. His younger brother - Aster - would not be surprised if answering the curious child was not on that temporary bucket list. With a mental scowl, Gaster could just hear his sibling mock him for the misfortune of a child being naturally curious.

"Where did you hear it from?"

Monotonous, bored-sounding, the skeleton's voice wasn't one many would willingly listen to, if you could help it. He reminded many of their boring history or english teachers from secondary school. All words and no personal expression. His neutral, blank face did not help in removing that comparison.

A little, cu- no. Not that word. But a little giggle reached his ears as the skeleton child clambered gracelessly onto his cloaked lap.

"Auntie Fell said that they were off to Leo's stag do tonight and that you weren't invited because you're rude and socially... aw... aw... aw..."

"Awkward."

"Socially awkward. What is that also?"

He sighed, placing the uncapped pen down, only to flick a non-existent eyebrow - well, eye ridge - up in exasperation as the kid stole the pen from his desk and failed at getting it into his pen pot. The adult grasped the pen with a helping hand and dropped it into the pot while his true hands were occupied with making sure the excitable child did not flop off his legs. As curious as he was, sleep flashed within lilac eyes.

"A stag do is a party where the male mate is taken out by his friends as a congratulations for his upcoming marriage. Socially awkward is where a person is too shy to go into social situations."

The cloaked - lilac to match his eyes - skeleton was silent for a minute before he decided to break the pleasant silence. Again.

"You're not socially awkward. You're just a mean old man."

Giggles followed this statement, quiet from tiredness. Believing the child to go to sleep, Gaster let the kid lay against his ribcage, clothed in a pitch black cloak not unlike the midget one covering up the tiny one.

"So, dad, what are you... doing?"

Within that sentence, the small one yawned and the adult monster sighed with a frustrated tone. Was he not going to get a break tonight? Judging by the squirming, no, he was not. Gaster scowled, consciously checking around the room and casting his magic around the house to see if he was truly alone before scooping up his charge and softly murmuring to his child, protected within his encompassing arms.

Even in singing, his voice didn't loose the monotone. It did soften, however, masking the plain component with splashes of affection. Gaster would rather die than admit anything stronger than affection. Deep within his upside down grey soul, an abstract noun referred to as 'love' blossomed with each syllable he intoned to his child. His Magneto.

"Day is done,

Gone the sun,

From the lake, from the hills, from the sky.

All is well, safely rest,

God is nigh."

A smirk, satisfied, loved and affectionate back, curled the black mouth of Magneto through the gleaming bone as the child settled as his father repeated the same lullaby - Magneto's favourite, he'll have you know - with a gentle swaying of his arms.

Hours later, the group returned from their night out, pleasantly buzzed but not absolutely drunk. Pictures were taken and knowing looks cast around when they laid their eyes on the teasing material of the usually awake Gaster asleep with Magneto encased by a father's arms. Aster murmured two words to the air, where Leo and the werewolf called Psycho Vinnie, Psycho or PV for short, stood.

"Cough up."


End file.
